Casuarina equisetifolia is a she-oak species of the genus Casuarina. The native range extends from Burma and Vietnam throughout Malesia east to French Polynesia, New Caledonia, and Vanuatu, and south to Australia (north of Northern Territory, north and east Queensland, and northeastern New South Wales). It is possibly native to Madagascar. The species has been introduced to the Southern United States and West Africa. It is an invasive species in Florida.
Casuarina equisetifolia was officially described Linnaeus in 1759 as Casuarina equisefolia. A type was designated by New South Wales botanist Lawrie Johnson in 1989. Common names include Coast Sheoak, Beach Casuarina, Beach Oak, Beach Sheoak, Whistling Tree, Coastal She oak, Horsetail She oak, and Coast She oak The specific name equisetifolia is derived from the Latin word equisetum, meaning “horse hair” (referring to the resemblance of the drooping branchlets to horse tails). The species has many common names including coastal she-oak, beach she-oak, horsetail beefwood, horsetail tree, Australian pine, ironwood, and whistling pine Filao Tree and Agoho.
There are two subspecies:
Casuarina equisetifolia subsp. equisetifolia. Large tree to 35 m (115 ft) tall; twigs 0.5–0.7 mm (0.020–0.028 in) diameter, hairless. Southeast Asia, northern Australia.
Casuarina equisetifolia subsp. incana (Benth.) L.A.S.Johnson. Small tree to 12 m (39 ft) tall; twigs 0.7–1 mm (0.028–0.039 in) diameter, downy. Eastern Australia (eastern Queensland, New South Wales), New Caledonia, southern Vanuatu.
It is an evergreen tree growing to 6–35 m (20–115 ft) tall. The foliage consists of slender, much-branched green to grey-green twigs 0.5–1 mm (0.020–0.039 in) diameter, bearing minute scale-leaves in whorls of 6–8. The flowers are produced in small catkin-like inflorescences; the male flowers in simple spikes 0.7–4 cm (0.28–1.6 in) long, the female flowers on short peduncles. Unlike most other species of Casuarina (which are dioecious) it is monoecious, with male and female flowers produced on the same tree. The fruit is an oval woody structure 10–24 mm (0.39–0.94 in) long and 9–13 mm (0.35–0.51 in) in diameter, superficially resembling a conifer cone made up of numerous carpels each containing a single seed with a small wing 6–8 mm (0.24–0.31 in) long.
Distribution and habitat
Casuarina equisetifolia is found from Burma and Vietnam throughout Malesia east to French Polynesia, New Caledonia, and Vanuatu, and south into Australia (the northern parts of Northern Territory, north and east Queensland, and northeastern New South Wales, where it extends as far south as Laurieton.
Thanks for the suggestion to Alan Mason – Deskarati